System of electrical distribution.



P.'M. LINCOLN, SYSTEM OF BLEOTRIGALDISTRIBUTION APPLICATION FILED JAN. 30,4909.

' Patented Jan. '2, 1912.

WITNESSES: 28 .30

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SYSTEM- OF ELECTRICAL DISTRIBUTION.

To all wlwm it may concern: 4

. Be itlmown that I, PAUL M. Lmoomr, a citizen of'the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a' new and useful Improvement in Systems of Electrical Distribution, of which the followmg is a specification.

My invention relates tosystems of trans mission and distribution for electrical energy, and it has special reference-to systems in which the energy is transmitted to numerous sub-stations at great distances from the generating station.

One of the objects ofmy invention is to provide improved means, in a system of the class above indicated,'for automatically cutting out a section of the transmission circuit. in case of a ground, a short circuit or other disturbance in said sect-ion.

Another object of my invention is to pro-1 ide means for preventing injury to the'lowvoltage windings of transformers embodied in systems of distribution where the highvoltage windings of the transformers are connected to very long transmission lines in which static disturbances are liable to occur.

lVhe'n a plurality of distant sub-stations are fed from a single generating station, a polyphasetransmission line, arranged in the form of a loop, is sometimes utilized for.

connecting the generating station and all of the sub-stations together, and, under such conditions, itis desirable to out out asection of the line without interrupting the supply of energy to any of the sub-stations whenever the transmission line is injured at any point between stations. According to my present invention, I provide means for auto mat-ically cutting out a predetermined section of the transmission line without necessarily interrupting the supply of energy to any of the sub-stations and, at the same time,-

rendering the injured section of the line dead in'order that it may besafely and speedily repaired.

' Figure 1 of the accompanying drawings is a diagrammatic view of a transmission system, the circuits of which are shown as single phase, for the sake of simplicity, and

a Fig. 2 is a diagrammatic view'of a section including 'two adjacent sub-stations of thesystem illustrated -in Fig. 1, the diagrams being illustrative of my. system of distr1bi 1 tion.

Specification. 0! Letters Patent. l Patented Jan. 2,1912. Application filed January 30, 1909. Serial No. 475,225.

plurality of sub-stations A, B and ,G are supplied with energy from a main generating station X by means of a single-phase system of distribution, the circuits of which are connected in a closed loop. The generating station comprises a generator '1, a pair of station switches 2 and-3, step-up transformers etand 5 and automatic circuit interrupters 6 and 7. Each of the sub-stations A,

-B and C comprises a transformer 8.'and a Referring to Fig. 1 of the drawings, a

pair of automatic circuit interruptersf?) and 10,"which are located-at the respective sides of the transformer. I i 1 The operation of the systemland thedetails of its auxiliary circultconnectionsmay be readily understood from the diagram of Fig. 2, to which reference may now behad. Tn Fig. 2, three-phase transmission circuit conductors 11, 12 and -13,'which correspond.

to the single-phase'transmission iineof Fig. 1, are shown. At distant points on the line conductors 11, 12 and 13, substation taps-14:,

15 and 16 and 17', 18 and 19 are severally connected to primary windings 20 and 21 of the transformers 22 and 23,through switches 24 aifi 25. The secondary windings 26 and 27 of the transformers 22 and 23 are connected to low-voltage distributing circuits 28, 29 and 30, and 31, 32 and"33. "In the substation A, circuit interrupters 34 and 35, correspondingte the interrupters 9 and 10' of- Fig. 1, are located at the respective sides of the taps 17, 18' and 19. The sub-station'B is similarly equipped with circuit inter-- rupters 36 and 37, and, by this arrangement, the switches 24and 25 may-be opened, if it is desired to interrupt the supply of energy to any one sub-station, and adjacent circuit interrupters, corresponding i to the interrup'ters 3 1 and 37 may be opened, if it is desired to cut outla section of the transmission line 11, 12 and 13, without interrupting the supply of energy to any of the sub-stations.

In order to render the system automatic, so that the proper. circuit interrupters will be opened in case the transmission circuit is injured or, grounded, Ilprovide a plurality of series transformers 38, 39, 40 and 41 at the sub-station B and transformers 4:2, 43, 44 and 45 .atthe sub-station'A. Each of the circuit interrupters is equipped with a closing coil 46 and-a pair of trip coils 47 and'. 48. The circuit interrupters are also proyided with auxiliary switches 49..and

master controllers or push button switches 50. The coils 47 and 48 of the circuit interrupter 36 are respectively connected to corresponding term'inals of the secondary wind- 5 ingsofthe transformers 39'and'38, the opposite terminals of the transformersecondary windings and theopposite terminals ofthe coils being connected to ground. The trip coils of the circuit "interrupters 37 are similarlyconnected to the windings'of the transformers 41 and 40,the coils of the interrupter 34 to the windings of the transform- '-ers 43"-a'nd 42 and the coils of the interrupter 35 to the windings of the transformers 45 and 44. The terminals of the trip' coils which are joined to the transformers 38 and 39 are also connected'by means of a plurality of auxiliary conductors 51 and 51 to similar points on the trip coils of the adjacent circuit interrupter in the sub-station C. The I corresponding terminals of the coils on the circuit interrupter 37 are connected'through conductors 52 and 53 to the-trip coils of the interrupter 34 and, similarly, the trip coils of the interrupter 35 are connected, through conductors 54 and 55, to corresponding tr1p coilsonthe main generating station interrupter which is'adjacent to it.

The operation of the system is as'follows: Assuming that the circuit interrupters are closed as indicated in the diagrams and that energy is being supplied from the generator 1, in difl'erent amounts,.to the sub-stations A, B and C, it is evident that the amount of 35 current traversing adjacent sets of the transformers, for example,'the transformers 40 and 41, and 42 and 43, will. be substantially the same, but if, for any reason, the trans mission circuit should be grounded or shortcircuited, it is evident that the currents traversing the transformers 40 and 42 or the currents traversing the transformers 41- and 43 would be opposed to each other and, consequently, either the trip coils 47 of the interrupters .37 and 34 or the trip coils 48 of these interrupters would be energized, as "hereinafter explained. Under normal conditions, the arrangement of the circuit con nections is such that, thevoltage generated. in the secondaries'of the transformers 40 and 41 is only requiredto force/a current through the auxiliary conductors 52 and 53, since the resistance of the trip coils '47 and 48 is high, relative to that of the auxiliary conductors which are connected in shunt relation thereto. Butwhen the main circuit conductors are grounded, the transformer secondary windings are opposed to each 1 "other and the effect is the same aslif thc auxiliary-conductors were interrupted and flleenhanced secondary voltage of the se- 'riestransformers is utilized-in energizing the trip coils of the respective circuitbreakers. Following the energization of the trip coils. thecircuit interrupters 34 and 37 will be actuated and the section of the transmissison line included between them .Will be. out out. By referring to thcdiagram of Fig. 1, it is evident that if the circuit interrupter 1O of the sub-station B and 7 0 the circuit interrupter 9 of the sub-station A are'opened, energy will still be supplied to. .both sub-stations by different routes but that a section of the loop is cut out.

-While in the arrangement illustrated, each 7 sub-station is equipped with two main line circuit interrupters, it may be preferable, in some cases, to supply onlyone, since the probability of frequently interrupting the circuit is remote. If only one interrupter is provided at each sub-station and the arrangement of series transformers is the same as before, it will then be possible to cut out a section of theline automatically by also cutting ofl the supply of energy'to one of the sub-stations. -When the interrupters have been opened, for .any reason, they may be closed by temporarily closing the corresponding push button switch 50. For example, if CltCllit interrupter 37 is opened, it may be closed by temporarily closing the push button switch 50 adjacent to it, 'which'completes a circuit from any convenient source su'chas*'asma-l'l'- transformer 56 through a conductor 57 aux- 9 iliary switch 49 which is now closed, switch 50, closing coil 46'of the interrupter 87 and conductor 58, to the opposite terminals of the transformer. As the interrupter is closed, the auxiliary switch-is opened, in a well known vmanner, in order to avoid the -necessity for continually energizing the magnet coil 46. v

In very high-voltage transmission systems, the neutral point of which is not grounded, it is very important to provide means for preventing the abnormal yoltage increases in the secondary windings 0 transformers which are connected to the circuit. 1 Should the high-potential line become grounded, even momentarily, the distribution of static potential in transformer windings causes a- .very marked potential disturbance in the low-voltage winding which might reach a voltage value several times greater than the normal potential of the low-voltage winding. In'order to' protect the transformer ,against disturbances of the character just referred to, I' have; rovided star-connected transformers 59 an 60, the terminals of which are connected to the lowvoltage distributing circuits of the sub-stations and the neutral points of which are; grounded. Itis preferable to make the transformers 59 and 60 of sufficient currentcarrying capacity to tr'ipthe u'sualf circuit" interrupters (not shown) of the'low-volta circuit of. the transmission system inn t e event of an abnormal disturbance upon'the highipotential circuit.

Modifications in the circuit arrangement and connections may be effected without deartingfrom the spirit and scope of my inention and those skilled in the art can readily adapt the imprm-ements set forth aboveto transmission circuits which are supplied with eitherdirect current energy or with single or polyphase alternating current en ergy.

I claim as my invention:

1. In a system of distribution, the combi- I nation with a source of energy, a high-voltage distributing circuit, a hut-voltage re ceiving circuit and a transformer interposed between the two circuits and having a deltaconnected secondary winding, of a star-connected auxiliary transformer connected to the receiving circuit and a ground connec tion to the neutral transformer.

2. In a' system of distribution, the combination with a sourceof energy, a distributingcircuit,'areceiving circuit and a transformer interposed between the two circuits point of the auxiliary my name this 18th day 0t Jan,

ground I v 

